Method of patching leather



Dec. 14 1926. 1,610,521

. K. L. HERRMANN METHOD OF- PATCHING LEATHER Filed April 8, 1925 INVENTOR Kfl/EL L. HEEEMHNN I 34.42:... 5.- BY

ATTORNEY Patented Dec. 14, 1926.

nears srA'rss' Fries.

KARL L. HEERMANN, OF DETROIT, MICHIGAN, ASSIGNOR TO THE STUDEBAKER COR- PORA'IION, OF SOUTH BEND, INDIANA, A CGEPOBATIOH OF NEW JERSEY.

METHOD OF IPA'I'CHIN 'G LEATHER.

Application filed. AprilS, 192-5. Serial No. 21,712.

This invention relates to the patching of leather and has for its objects the providing of a form of patch that when finished will not be detectable, which will provide means whereby patched leather will be as strong as unpatched leather as far as practical uses are concerned, which for practical results may be used for any purpose that unpa-tched leather may be used for, and which will be economical and practical to use.

Up to the present time, so far as I am aware, there has been no practical method of patching cuts, gouges, scratches or digs in the surface of a piece of leatherso that it may be used in any place or for any use that unpatched leather may be used in or for. I am aware that shoe makers have patched holes or ruptures extending clear through a piece of leather by cementing and sewing another piece of leather .to the back of each piece over such hole or rupture, but this method produces an extra thickness of material at the point of, patching and does not entirely conceal such hole or rupture, and is not used where the hole or rupture does not extend clear through the piece. An improvement on such method is set forth in my co-pending patent application on patching leather, filed July 18, 1923, Serial Number 654,480.

The advantages of providing an undetectable patch for such a cut, gouge, scratch or dig is particularly apparent in connection with upholstery leather, which leather is commonly of split skin and usually coatfinished on its grain or naturally outward side. lVhere such a piece of leather is needed for an automobile cushion, for instance, it is preferably in one piece and of such a size as will take one-half of the. ordinary sized hide, and it must be uniformly free from surface defects and of uniform strength. VVheresuch a piece of leather, in the past, has had a cut, gouge, etc, in its outer surface of a size to be apparent after finishing, it has been necessary to cut out a strip across the width of the piece in which such cut or gouge is embodied. and sew the acceptable parts together, taking care that the seam thus formed will fall in one of the folds of the leather between the panels of the.

cushion. l/Vhere there are two such cuts or terial cut out must'be of such a width that both seams fall in the folds of the cushion panels, and in such a case it is evident that there is a substantial loss of leather. Due to this loss and to the expense of cutting and sewing, the natural result is that hides having such defects sell for a substantially less amount than perfect hides, and are more or less of a loss to their owners.

Having the above in mind, it is the principal object of the present invention to provide a method for eliminating such apparent defects as are above referred to whereby such leather may be used for any practical purposes that leather not having such defects may be used, and such method consists of mechanically removing from a piece of leather containing such a gouge, out, etc., a smaller piece of leather therefrom of a predetermined size and shape, about, and in which is'located, such gouge or cut. The piece of leather thus being removed is preferablv ofless thickness than the thickness of the leather from which it is removed so that the depression caused by its removal does not extend through the normal thickness of the leather, the removing of such piece of leather being accomplished by a mechanical skiving operation whereby the depression formed thereby is very shallow and gradually tapering from the edges to the bottom at a very small angle. A patch, which has also been formed by a mechanical skiving operation to the exact size and shape of the depression, is then inserted in the mechanically formed depression and cementitiously secured therein. This patch is so broadly bonded in the depression that the leather is freely bendable or distortable without liability of squeezing or working the patch out of place by flexure of the patched portion of the leather duringthe wear and strains of use. After such patch has been applied. the leather may be finished if desirable or necessary and if the leather is to be used forupholstery purposes it may be coated and grained in the conventional manner, thereby concealing any trace of the patch or previous cut, gouge, etc.

It is important that the edgeof the patch i be thin and regular or free from irregularities as must also be the surfaces of the de-' 7 a I I pression, because if they are present, pitsor.

trough-like conditions will be present at the junction of the edge with the skin and thereby fol-1n smaller depressions around the edges of the patch in whole or in part with the result that very frequently a graining board used in the grain finishing operations will pull the patch out of place.

The above being among the objects of the present invention, the same consists of certain features of construction and combination of parts to be hereinafter described, with reference to the accompanying drawing, and then claimed, having the above and other objects in view.

In the accompanying drawing which illustrates a suitable embodiment of the present invention, and in which like numerals refer to like parts throughout the several different views,

Figure 1 is a plan view of a piece of leather having a gouge in its surface as previously described.

Figure 2 is a sectional view of the piece of leather taken on the line 2 2 of Figure 1.

Figure 8 is a'pla'n view of the same piece of leather as in the previous views, showing the portion which forn'ierly included th gouge cut away to provide seat for a patch, the former position of the gouge being indicated by dotted lines.

Figure 4 is a sectional view of the piece of leather taken on the line 44 of Figure 3, as prepared to receive a patch, the former position of the gouge being; indicated by dotted lines.

Figure 5 is a plan view of a patch which hasbeen prepared for the depression formed by cutting away the leather about and including the gouge.

Figure 6 is a section of the patch on the line 66 of Figure 5.

Figure 7 is a sectionalview taken through the center of the patch of the piece of leather and-the patch shown in theprevious views after they have been ceinentitionsly joined or bonded together in the manner prescribed.

Figure 8 is a sectional view correspond inn; to Figure 7 but in which a conmntional coat finish has been applied over the normally exposed surface thereof.

Figure 9 is a side elevation of a inachinc which nary be conveniently enualoyed for slriving out both the depression in the leather and the patch therefor.

Figure 10 is a view of the cutting; mechanism of the machine of Figure 9 taken from below the same and looking upward Figure 11 is a sectional view of the cutting mechanism shown in Figure 10, taken on the line 11-11 of Figure 10.

In the drawings is shown a piece of leather 15 which has a gouge 16 in its surface, which gouge extends to such an extent into the leather, but not all the way through it, that a hen if it were not possible to conceal. it by properly patching it, it would necessitate the rejection of such piece of leather for upholstery uses, particularly if were situated on the face side thereof. it is, of cour grinderstood that the thicl: ess of the leather shown is greatly exaggerated to more clearly debe the invention, each pieces of leather being, in ordinary practice, much thinner and much more flexible. The patching of such ;oug;c 16 is preferably accomplished after splitting); of the hide and before finishing the same, so that the operation of working down the split or finishing it will substantially, it not entirely, eliminate any only-.21.- irl of the same.

The gouge 16, as shown in Figures 1 and 2, is prepared, as shown in Figures 3 and t, for patching; by removing acertain amount of the leather about, and in which is included, the gouge 16. The leather so remov d is preferably of a predetermined size and shape, which is readily acco1n-- plished and made practically possible by H26: is or the machine herein later described, to iorn'i a very shallow depression 17 the sides of which eatendtrorn the edges of such depression to the botton'i of the same at a very sli; flat angle. pression l? is cemented or otherwise suitably secured in matching relation with a patch 18, which is formed from a piece of leather in exactly the same manner as the depression 1'? 'is formed, and which is, of exactly the me size, shaoe and dimensions as the depr ,n 1'7. inns nuch as the patch 18 oi the same size and shape as the depress on 1?, itwi l be apparent that is up- .D rg e bonding surhi-ue coupled with the thin exihlo marginal edges of the patch inures at bending or lie of the leather nt of patching will not loosen the ch, nor will it cause the leather at this to be noticeably stitl" or unyielding, addition, such patched portion 1 have found to be of equ l strens jth to any uupatched portion of the leather.

When such patch is applied to the normally unexposed and unfinished sid. of the leather it is d llicu t to locate such a pzfiched l'uishportion even without any subsequent inc; operation and when it is located nor v e: osetl surface and is s l)Scl119111 ly finished. pzu'ticularlv if a .lini 1 coat 0" Martina" material such as ruined t is impossible to ch, and in ch a case such a patched piece of leat u may be used for any practical purposes that an unpatchcd distinnun The prepared tie-- llitl -ard depressions.

piece may be used for, thereby effecting considerable saving of leather and money.

In order to facilitate such patching and to make the same practical, economical, and to place it on a so-called production basis, it is desirable to form such depressions as pre viously described to one of a number of standard or set sizes and contours and to provide standard patches to lit such stand- In such an event the patches and depressions may be prepared separately and at different times and places if so desired, and in the operation of patching the leather the patch may be applied to any corresponding depression in the leather with an assurance that it will fit perfectly.

To realize such a condition it is necessary to provide means for forming uniform patches and uniformly preparing the depressions in tluleather to correspond therewith. Although there are several methods that might be employedfor this purpose, I have illustrated in Figures 9, 10 and 11 one particular machine with which this may be readily, easily and accurately accomplished, and which machine is the subject of my copending patent application on Machine for cutting patches and the like filed April 14, 1924, Serial Number 706,433. This machine is such that any number of patches may be made, or depressions formed, to duplicate a standard or fixed size of patch or depression, and is such that a smooth and unbroken matching surface of such patch or depression is obtained and previously de scribed as being necessary.

This machine is composed of a base member 20 having an upright post 21 which supports and upon which is swiveled an arm 22 which journals and supports the cutting apparatus or'head. A nut 23 threaded on the post 21 below the arm 22 provides vertical adjustment of the arm 22 and therefore of the cutting head.

The removal of the leather about and including the gouge 16, as shown, may be acused and the method employed is to support a button such as 24 on the base 20 directly under the cutting head, place the leather at the point where the depression is to be formed, or the patch is to be formed, directly over the-button, draw the leather down in close relationship with the button and pass the knife horizontally across it in the required close proximity to it. The button 24 is soshaped on its upper surface, against which the leather rests, as to correspond to the exact shape of the depression to be formed, or the patch to be cut out,and it will be evident that when the leather is drawn down tightly over the top of the but ton and a knife is passed horizontally over the button in relatively close but spaced relation. thereto, all the leather above the horizontal plane of knife edge will be removed, and this removed portion will be identical in shape, when either its upper or lower surface is positioned flat in one plane, to the upper corresponding surface of the button, and also, that when the piece of leather from which such piece has been removed is positioned flat, the depressiorformed by such removal will be exactly co1nplementary to the top surface of the button and to either surface of the piece removed, or patch, when the opposite surface of such patch is flat' It will be further evident that by this method any number of such depressions or any number of patches, both of which are formed by exactly the same opera-' tion, may be formed to exactly the same size, shape, contour and dimensions.

lVhile I have shown in the drawings a button 24 having a spherical top surface, which accordingly causes circular depressions and patches to be formed in the cuttingmperation, it will be evident that such top surface may be changed in size, shape, contour and dimensions to agree with any size, shape, contour and dimensions of de pression or patch which it may be desired to form, such as in case of a patch for a relatively long and narrow knife cut, a long narrow button may be used. If such a cut is too long for the dimensions of the machine'to form a patch for it in one operation, separate parts of it may be patched in successive operations until the whole is patched,

I have found that if a ,knife 'is passed over the button directly from one side of it to the other, the knife has a tendency to lift the leather after it has passed over the center of the button 24, thereby causing thedepression 17 or patch 18 whichis being prepared to not exactly match the upper surface of the button 24 as desired, but has the effector" digging into the leather 15on passing over the center of the button which results in a sharper angle to that side of the depression or patch as the case may be. I have found that by revolving the knife, so as to begin cuttingaround the periphery of the depression or patch, and gradually bringing it in to the center of the button 24 in a spiral movement, a depression 17 or patch 18 results which corresponds exactly to the upper surface of the button 24, and the scout surface of the depression or patch is smooth and free from any waves or other imperfections.

in the machine shown in the drawing a lib") llil iis

cutting head isprovi'ded with mechanism to revolve the knife and to draw it to the center as above described. This cutting head is supported on the swiveled' arm22 and has a vertical shaft 25journaled in and supported by the arm 22, a crank or handle 26 being secured to its upper end for the purpose of operating it, and an arm 27 being secured to its lower end. A knife supporting member 28 is pivoted at 29 to the arm 27 to swing in a horizontal plane and is provided with a detachable knife blade 30, the center of which is preferably on an aroof a circle whose center is at 29 and which al o passes through the axial line of the shaft 25. A track member 31 whose lower face is in a horizontal plane is non-rotatably secured to the lower face of the outer end of the arm 22 about the shaft 25 and above the arm 27 and knife supporting member 28. A spiral T-shaped groove or track 2 is cut in the lower face. of the track member 28 as shown in Figures and 11. A pin or finger 33, secured to the member 28 adjacent the knife blade 30 and extending upwardly therefrom engages the groove 32, and may be either merely guidedtherein or may'also serve to help support the member 28 by reason of its head portion engaging the head portion of the T- groove. It will be evident that the pin 33 engaging the groove 32 controls the position of the knife blade 30 in relation to the center of the button 2-l when the arm 22 is swung over to bring the cutting head directly over the button 24, or, in other words, when the axis of the shaft 25 and the axis of the button 2% are in line. It will. also be apparent that when the handle 26 is turned or rotated. causing the arm 27, member 28 and knife blade 30 to turn therewith, the knife blade 30 will be caused to move outwardly or inwardly from or to the axis of the shaft 25, and consequently the butt-on 24 when in the position above referred to, in a manner corresponding to the direction in which the randle is turned, thus causing the knife blade 30 to have a rotary motion about as well as a transverse movement to or from the center of the button 24. This movement, it has been found, results in a depression or patch that perfectly matches the button 24 and gives a clean, even, cut surface. For this reason the machine particularly lends it self to patching leather in the manner above described.

In the operation of preparing a piece of leather having such agouge or similar defeet as 16 for patching by the machine illustrated and described, the handle 26 is first revolved to cause the knife blade 30- to move to its extreme outward position, the arm 22 being then swung around the post 21 to carry the cutting head away from its position over the button 24, the leather is placed over the button 22L with the gouge 16 directly over the top surface of the button 24 and facing upwardly, the leather 15 being then drawn down tightly against the upper surface of the button 24 by a ring (not shown) or other suitable means, the arm 22 is swung back to bring the axis of the shaft 25 in line with the axis of the button 24, and the handle 26 is rotated to cause the blade 30 to rotate around and to approach the center of the button 24, thereby removing the leather about and including the gouge 1G and forming the depression as at. 17. In identically the same manner, and by identically the same operations, a piece of leather having a perfect surface may be placed over the button 24 and a portion removed therefrom, such removed portion in the case of a piece of leather having a perfect surface, providing a patch 18 for the depression 17 as previously described.

Y'i hile in the above description reference has been made solely to the patching of leather, it will be understood that the process is equally applicable to other materials capable of like uses, and the term leather in both the specification and the claims is meant to include all materials of this nature.

Formal change may be made in the specific embodiment of the invention described, without departing from the spirit and substance of the broad invention, the scope of which is commensurate with the appended claims.

lVh'at I claim is 1. The process of filling in imperfections in the surface of a sheet of leather which consists in mechanically removing a portion of the material about and including said imperfection to form a relatively shallow depression having gradually sloping side walls. in mechanically forming a patch from a body of similar material and of substantially the same area, contour and sloping complementary surface as the said depression, in cementitiously securing said patch in said depression in matching relation therewith, and in finally finishing said leather to completely cover the same including said patch.

2. The process of filling in imperfections in the surface of a sheet of leather, which consists in first mechanically removing a portion of such material of a predetermined size, shape and contour about and in which is included said imperfection to form a shallow depression having gradually taper ing side walls and a substantially flat bottom wall, in mechanically forming a patch from a body of similar material and of substantially the same size, shape and contour of the said depression, and in finally applying to and cementitiously securin said patch in said depression.

3. The process of filling in imperfections in the surface of a sheet of leather which consists of mechanically cutting away said material about and including said imperfection to form a depression in the surface of said material of predetermined area and contour and having widely divergent tapered side Walls and a substantially flat bottom Wall, in preparing a patch having a complemental tapered edge and of substantially the same area and configuration as that of said depression and in applying said tapered edge patch to said depression and securing the same therein to said bottom and side Walls,

thereby to present a substantially flush outer surface of the patch and the patched material.

Signed by me at Detroit,rMichigan, U. S. A., this 2nd day of April 1925.

KARL L. HERRMANN. 

